Knob structure



J. A. GITS ET AL KNOB STRUCTURE Filed July 29, 1937 Patented Aug. 29,1939 UNITED STATES PATENT-OFFICE KNOB STRUCTURE Joseph A. Gits and JulesP. Gits, Chicago, ill. 1 Application July 29, 1937, Serial No. 156,288

4 Glaims.

This invention relates to knob construction and more particularly to amolded dial knob adapted to be mounted upon a spindle or shaft which itactuates.

Although apparently simple in construction, dial knobs of moldedconstruction have heretofore presented-a difficult problem in theirmanufacture. Knobs of this type must be provided with securing meansthat will secure them to the shaft upon which they are carried so thatthey may turn the shaft when rotated and not be displaceable except whendesired. Uneven shrinkage has been exceedingly troublesome in themolding operation of devices of this type, and has caused the adoptionof expensive forms of securing means, some of which areeii'ective andothers of which do little to overcome the uneven shrinkage or provide aproper and effective connection between the knob and shaft.

It is an object of the invention,therefore, to provide a simple andinexpensive form of dial knob that is so designed as to admit of auniform molding operation and provide thereby an integral unit havingparts of substantially uniform thicknesses whereby to overcome unevenshrinkage, and further to provide as a part of said integral unit aninexpensive but very efiective securing means between the knob structureand the shaft so that the knob may rotate said shaft and be axiallydisplaceable only when desired.

A further object of the invention is to provide a dial knob of the typedescribed having the characteristic mentioned in which a minimum ofmaterial may be used although providing a structure of exceptionallygreat strength.

A still further object of the invention is to provide this type of knobin which a simple but effective form of securing means may be providedbetween the knob and the spindle to which it is attached.

To this end provision is made in the form of securing means that may beembodied as part of the knob and also as part of the structure of thespindle whereby added parts, such as metallic inserts, set screws,spring inserts, or the like, may be eliminated. It is found that with asimple form of securing means the problem of molding the knob body issimplified and a structure may be provided that more readily eliminatesthe problem of uneven shrinkage in the molding operation and provide amore. efllcient, simple and inexpensive structure.

In ordertc apprise those skilled in the art how to construct andpractice the invention, I

shall now describe several preferred embodiments in connection with theaccompanying drawing which forms a part hereof.

In the drawing:

Figure 1 is a perspective view of a knob em- 15 bodying'the invention,which knob is shown as mounted upon a shaft or spindle;

Fig. 2 is a vertical section of this knob illustrating the securingmeans holding the knob to the spindle;

Fig. 3 is a view similar to Fig. 2 but with the knob and spindleseparated;

Fig. 4 is a rear view of the knob;

Fig. 5 is a transverse section ofthe knob taken along line 5-5 of Fig.3; 1

Fig. 6 is a view similar to Fig. 3 but illustrating a slightly modifiedform of knob embodying the invention;

Fig. '1 is a view similar to Figs. 3 and 6, but illustrating anotheralternative embodiment of the invention;

Fig. 8 is a perspective view of the knob looking toward the rear facethereof, and

Fig.- 9 is an end view of the form of knob shown in Fig. 7-

The dial knob I illustrated in Figs. 1, 2 and 3 comprises essentially auniformly molded integral unit composed of two parts, to-wit, a head 2and a shank 3. Head 2 is preferably designed to be of substantialuniform thickness throughout, as will be noted in Fig. 2, while shank 3is preferably formed of a plurality of Walls likewise of substantialuniform thickness. These walls are preferably made by providing cavities4 in shank 3 during the molding operation. In the form illustrated,these-walls are preferably arranged as concentric shell or sleeve-like.members I and 6 that are joined by inter-connecting spacing ribs I. A

It will be noted therefore that theintegral 4o body is uniformly moldedinto a structure having its parts of relatively uniform thicknesses sothat any tendency for uneven shrinkage in the molding operation iseliminated. Inner concentric sleeve-like member 5 is furnished with anopening 8 adapted to receive the end of a spindle 9 to which knobs ofthis type are adapted to be carried to rotate or to act as a handle formoving this spindle from one position to another. We preferably providea simple securing means between knob I and spindle! in the form ofcorresponding irregularities along the surfaces of opening 8 and spindlei. such irregularities bein for example, projections, ribs or beadsengageable in corresponding grooves whereby these 5 parts are securedtogether against relative rotation and accidental axial displacement.

As illustrated in the embodiment shown in Figs. 2 and 3, the inner wallof sleeve 5 forming central opening 8 may be provided with an annularhead or projection l0 arranged to slip into an annular groove I l inshaft 9. By providing an exceptional close fit between the shaft 9 andthe wall of opening 8, we are able to secure a snug fit between theseparts. However; we preferably provide knob I of a material, such ascellulose acetate, which will yield slightly within certain limits whenput under pressure. By limiting the thickness of concentric members 5and 6 which may be advantageously accomplished by virtue of the cavityformation provided by cavities 4 between these parts, the innerconcentric member 5 may be made to yield slightly when bead I9 is forcedover the end l2 of shaft 9 until this bead l9 dropsinto groove II. Tosecure a snug fit in an axial direction between knob l and shaft 9, wepreferably make shaft groove H slightly larger than bead l9. When bead Illis slipped over the forward end or head l2 of shaft 9, it will dropinto'groove l I, but will rest against the forward portion I3 of thesame, as illustrated in Fig. 2, to effect a cam-like action tending topull and hold knob l upon the end of shaft 9 It will be apparent thatthis cam action between bead l0 and its larger groove II willadvantageously take up any looseness between the parts due to slightvariations in manufacturing clearances.

A specific form of securing means preventing relative rotation betweenknob l and shaft 9 may include a projection or rib I l integrally formedin the molding operation upon the inside face of head 2, whichprojection or rib I 4 will cooperate or engage in a similarly shapedgroove l5 formed in the tip [2 of shaft 9. It will be apparent that.

when rib or projection l4 aligns with groove l5, the spring action ofbead l0 tending to return to its normal position will snap into positionin groove H and hub against the forward edge l3 so as to hold knob ltightly upon the shaft and prevent accidental axial displacement butpermit ready removal of this knob, if a pulling force sufficient toforce bead l0 out of groove H and over end l2 of shaft 9 is employed.

If so desired, rib M on the inside of head 2 may be eliminated and agroove l8 provided in lieu thereof, thereby permitting the use of anequivalent rib or projection l9 on shaft 9, as illustrated in Fig. 6,whereby, when knob l is slipped upon the end of shaft 9, rib orprojection l9 on this shaft will enter this groove l8 formed in head 2.

Another form of connection between knob l and shaft 9 is illustrated inFig. 7. A U member 20 may be molded in head 2 so as to project forwardlyfrom its inside face whereby to engage in a corresponding recess 2| inthe end face of shaft 9. Obviously, different forms of securing meansmay be provided, as illustrated herein, either to prevent axialdisplacement of knob I from shaft 9, or to prevent relative rotationbetween these parts.

As previously mentioned, knob i may be molded of any suitable material,such as cellulose acetate, and formed as an integral body of uniformlymolded parts to prevent uneven shrinkage, which heretofore has causedconsiderable trouble and expense. Usually a dialknob is provided with alarge forward face that may be either fiat or curved. If unevenshrinkage occurs, it will usually show itself across this face anddetract from the appearance of the knob. We find that to secure uniformshrinkage at head 2, it is preferable if not quite essential to providethe walls or parts forming the rearwardly projecting shank 3 likewise ofsubstantially uniform thickness. foregoing description that we are ableto provide shank 3 of walls or parts of substantially uniformthicknesses by virtue of the cavity formation provided by cavities 4 andthe centrally located opening 8 in member 5 that receives shaft 9.Moreover, it will be-apparent that the securing means employed hereinbetween knob I and shaft 9 may be integrally formed without affecting inany way the uniform molding of knob i into parts of substantiallyuniform thicknesses. As previously explained, the material, out of whichknob I may be molded, may be suificiently springy in character to yieldslightly under pressure. In the event it is desirable to adopt knob l toa shaft having a slightly smaller diameter than originally contemplatedfor the size of knob made, it is apparent that the variation may beeasily compensated for by making bead l0 slightly larger, which willeliminate the necessity of changing the entire mold to increase the sizeof the knob. Likewise, bead It may be made smaller if shaft 9 should beslightly larger than originally contemplated for the size of opening 8provided, and the inner sleeve 5 may then be slitted, as illustrated at2 2, so that it may readily slip upon the end of the shaft to allow thisbead ID to enter groove ll.

Without further elaboration, the foregoing will so fully explain thegist of our invention that others may, by applying current knowledge,readily adopt the same for use under varying conditions of servicewithout eliminating certain features, which may properly be said toconstitute the essential items of novelty involved, which items areintended to be defined and secured to us by the following claims.

We claim:

1. A knob of the type .described adapted to be secured to a shaft torotate the same comprising a molded body having an opening therein forsaid shaft, a bead on said body within said opening adapted to cooperatewith a groove formed in said shaft to prevent axial displacement of saidbody from said shaft, the rear wall of said opening being engaged by theend of said shaft to limit its axial movement, said bead beingrelatively smaller than said groove and positioned relative to said rearwall to engage the forward portion of the wall of said groo've wherebyto tightly hold said body upon said shaft by a snap engagement.

- 2. A knob of the type described adapted to be secured to a shaft torotate the same comprising a molded body having an opening therein forsaid shaft, an annular bead on said body within said opening adapted tocooperate with an annular groove formed in said shaft to prevent axialdisplacement of said body from said shaft, means engageable by saidshaft to limit its axial movement in said opening, said head beingrelatively smaller than said groove and positioned relative thereto toengage the forward portion of the wall of said groove whereby to tightlyhold said body upon said shaft, and means between said body and saidshaft to lock said body against relative rotation upon said shaft.

3. A knob of the type described adapted to be attached to a spindlecomprising a molded body It will be apparent from the I of plasticmaterial'having a head and a shank, said shank being provided with aplurality of recesses forming a plurality of yieldable walls, therebeing a substantially centrally located spindle opening of approximatelythe same diameter as said spindle, and a bead formed on one of saidwalls and lying within said opening adapted to cooperate with a groovein said spindle, said wall yielding to the pressure upon said head uponthe insertion of said spindle in said opening, said wall returning toits original position when said bead drops into said spindle groove.

4. The combination with a molded body of plastic material adapted to bemounted upon a spindle, there being an opening in said body to receivesaid spindle and means to limit the distance said body'may axially moverelative to said spindle, of means for holding said body upon saidspindle, said means being carried by said parts and comprising a beadand a groove, said bead being smaller than said groove and positionedrelative to said movement limiting means to engage the forward portionof the wall of said groove whereby to hold said body tightly upon saidspindle by a snap engagement.

JOSEPH A. GITS.

JULES P. GITS.

